# Does this type of ON-ON switch exist?

#### Cyclicz

Joined Apr 17, 2017
62
Simplistic question because I happen to know little about switch types. If it exists what's it called? The diagram is attached. In position 1 the points x-q and u-y and p-z are connected. In position 2 the points y-z and x-p and q-u would be connected. Normal on-on switches would break the series of the line not being monitored.

Visual

#### Cyclicz

Joined Apr 17, 2017
62
A circuit to do the same thing using a switch would also fit my needs.

#### AlbertHall

Joined Jun 4, 2014
12,071
You could do this with a 4 pole 2 way switch. Connect the poles of the switch to q, u, p, and z.

#### crutschow

Joined Mar 14, 2008
30,080
You could use a 4PDT switch.
Below is the diagram (shows two DPDT because I didn't have a 4PDT symbol).

Note that, depending upon the circuit, you probably shouldn't move the switch when the circuit is energized, since the circuits will be momentarily open circuit during the contact transfer.

#### Cyclicz

Joined Apr 17, 2017
62
You could use a 4PDT switch.
Below is the diagram (shows two DPDT because I didn't have a 4PDT symbol).

Note that, depending upon the circuit, you probably shouldn't move the switch when the circuit is energized, since the circuits will be momentarily open circuit during the contact transfer.

View attachment 124932
It will not matter if the circuit is momentarily open but I do want the action to happen with the flip of a singular switch

#### Cyclicz

Joined Apr 17, 2017
62
Whoops well ignore that last part about a singular switch as you don't have the icon. Can't seem to edit the reply

#### Cyclicz

Joined Apr 17, 2017
62
seems I have found one thanks for the help.
Here

Will flipping the switch whilst power is flowing cause voltage spikes perhaps or anything that would damage the ampmeter?

#### crutschow

Joined Mar 14, 2008
30,080
seems I have found one thanks for the help.
Here

Will flipping the switch whilst power is flowing cause voltage spikes perhaps or anything that would damage the ampmeter?
There were many 4pdt's shown this reference in post #4.

Whether flipping the switch will damage anything depends upon the circuits.
As I noted, when the contacts are moving, the circuits will be momentarily open circuited, so what will they do when that happens?

#### Cyclicz

Joined Apr 17, 2017
62
I'm seeing a lot of these types of switches are AC rated. Again I'm not the smartest when it comes to switches but I've been told using D.C. On an AC switch is a big no no. Not quite sure that any of these switches could handle managing a 5v 20amp line and an 12v 10 amp line.. Perhaps some light could be shed?

#### crutschow

Joined Mar 14, 2008
30,080
I'm seeing a lot of these types of switches are AC rated. Again I'm not the smartest when it comes to switches but I've been told using D.C. On an AC switch is a big no no. Not quite sure that any of these switches could handle managing a 5v 20amp line and an 12v 10 amp line.. Perhaps some light could be shed?
An AC rated switch will readily carry the same amount of DC current as AC if it doesn't have to switch the current.
Do you need to have the circuits active when you switch the ammeter between them?

One way to prevent a large glitch if you need to switch the loads hot is to add a diode across each connection.
The diode will carry the current when it's switched, thus limiting the transient voltage to less than a volt (this only works if the ammeter drop is less than a half volt when operating, which it likely is).

#### Cyclicz

Joined Apr 17, 2017
62
An AC rated switch will readily carry the same amount of DC current as AC if it doesn't have to switch the current.
Do you need to have the circuits active when you switch the ammeter between them?

One way to prevent a large glitch if you need to switch the loads hot is to add a diode across each connection.
The diode will carry the current when it's switched, thus limiting the transient voltage to less than a volt (this only works if the ammeter drop is less than a half volt when operating, which it likely is).
Well since this is for a power supply I'd like to switch the leads hot. The only thing I'm really worried about in this instance is the safety of my meter (because nothing will be connected to the power supply when I flip the switch) so I'll probably grab some diodes and see how it works out.

#### Cyclicz

Joined Apr 17, 2017
62
I feel so silly asking so many questions, but in what layout am I hooking up the diodes?

#### crutschow

Joined Mar 14, 2008
30,080
I feel so silly asking so many questions, but in what layout am I hooking up the diodes?
This is how the diodes would be connected for the polarity shown.
That way the diodes momentarily carry the current when the contacts transfer from one position to the next.

#### Cyclicz

Joined Apr 17, 2017
62
This is how the diodes would be connected for the polarity shown.
That way the diodes momentarily carry the current when the contacts transfer from one position to the next.
View attachment 124954
what are the specifications of the diode this circuit uses whilst running 12v at 10 amp on line a and 5v at 20 amp on line b? I'm getting glitches off the diodes I'm running, maybe they need to be the same wattage?

#### crutschow

Joined Mar 14, 2008
30,080
what are the specifications of the diode this circuit uses whilst running 12v at 10 amp on line a and 5v at 20 amp on line b? I'm getting glitches off the diodes I'm running, maybe they need to be the same wattage?
How much is the glitch?
Where are you measuring it?

The diodes only have to carry the current for the few ms it takes the contacts to transfer.
1A diodes such as a 1N400x should work, since they have a 30A surge rating, but larger diodes would reduce the glitch.

#### Cyclicz

Joined Apr 17, 2017
62
How much is the glitch?
Where are you measuring it?

The diodes only have to carry the current for the few ms it takes the contacts to transfer.
1A diodes such as a 1N400x should work, since they have a 30A surge rating, but larger diodes would reduce the glitch.
All I have access to (with my area and time frame) right now is a local shop that sells NTE parts. Would an NTE586 perhaps suite the purpose? The glitching I'm getting is being measured with a small oscilloscope set to voltage and I think it's just because the diode I'm using currently isn't good enough.

#### crutschow

Joined Mar 14, 2008
30,080
All I have access to (with my area and time frame) right now is a local shop that sells NTE parts. Would an NTE586 perhaps suite the purpose? The glitching I'm getting is being measured with a small oscilloscope set to voltage and I think it's just because the diode I'm using currently isn't good enough.
That dioe should work as long as its forward drop is greater than the ammeter you are using (Schottkys have a lower forward drop than standard junction diodes).

So what is the glitch voltage magnitude?

#### ian field

Joined Oct 27, 2012
6,536
You could do this with a 4 pole 2 way switch. Connect the poles of the switch to q, u, p, and z.
The circuit posted by the TS looks like a DPDT and looks fine as it is.

It does need to be a break before make type and not make before break.

.

#### Cyclicz

Joined Apr 17, 2017
62
That dioe should work as long as its forward drop is greater than the ammeter you are using (Schottkys have a lower forward drop than standard junction diodes).

So what is the glitch voltage magnitude?
Well technically I'm going to be using a shunt resistor and a Digital Panel voltmeter to read amperage which probabally doesn't affect much hopefully. Anyhow I'm going to go fetch myself some New diodes that will work nicely and see if that fixes the glitching. The voltage spikes with my old diodes are no more than .6v but it still has potential to harm components...

#### crutschow

Joined Mar 14, 2008
30,080
..............
The voltage spikes with my old diodes are no more than .6v but it still has potential to harm components...
That voltage is unlikely to harm any typical components.